练习一：计算机岁一个数，猜数大小。

    number = random()%100 +1;
        guessNumber = 90;
        while (guessNumber != number){
            if (guessNumber > number) {
                printf("大了");
                count++;
            }else{
                printf("小了");
                count++;
            }
            
        }
        printf("猜了%d次",++count);
    }

练习2:求平均数

//
//  main.m
//  CTest
//
//  Created by liushuang on 2023/4/4.
//

#import <UIKit/UIKit.h>
#import "AppDelegate.h"
int inputNumber = 0;//每次输入的数
int sum = 0;//总和
int count = 0;//猜次数

int main(int argc, char * argv[]) {
    NSString * appDelegateClassName;
    @autoreleasepool {
        // Setup code that might create autoreleased objects goes here.
        appDelegateClassName = NSStringFromClass([AppDelegate class]);
        printf("hello world");
        scanf("%d",&inputNumber);
        while (inputNumber != -1){
            sum += inputNumber;
            count++;
            scanf("%d",&inputNumber);
        }
        printf("平均数是%f",1.0*sum/count);
    }
    return UIApplicationMain(argc, argv, nil, appDelegateClassName);
}

练习3: log2 X 输入一个数a，log2的x次幂 是a，求x。

//
//  main.m
//  CTest
//
//  Created by liushuang on 2023/4/4.
//

#import <UIKit/UIKit.h>
#import "AppDelegate.h"
int inputNumber;//每次输入的数
int ret = 0;//次幂数
int temp;

int main(int argc, char * argv[]) {
    NSString * appDelegateClassName;
    @autoreleasepool {
        // Setup code that might create autoreleased objects goes here.
        appDelegateClassName = NSStringFromClass([AppDelegate class]);
        printf("hello world");
        scanf("%d",&inputNumber);
        temp = inputNumber;//小套路：提前存一下免得打印改变。
        while (inputNumber > 1){
            inputNumber /= 2;
            ret++;
        }
        printf("%d是2的%d次幂",temp, ret);
    }
    return UIApplicationMain(argc, argv, nil, appDelegateClassName);
}